Update python versions in CI

[catanzaromj]

An attempt to modernize the CI with up-to-date python versions as described in #72.

This PR:

• Updates the CI runners to run python 3.7 - 3.12.
• Updates persistence images code to modern typing and their tests.
• Fixes broken persistence landscape test.
• Fixes broken wasserstein test.

[codecov]

Codecov Report

Merging #73 (e5e71ad) into master (c35fa04) will decrease coverage by 0.02%.
The diff coverage is 64.83%.

❗ Current head e5e71ad differs from pull request most recent head c7ee8b4. Consider uploading reports for the commit c7ee8b4 to get more accurate results

@@            Coverage Diff             @@
##           master      #73      +/-   ##
==========================================
- Coverage   75.90%   75.89%   -0.02%     
==========================================
  Files          20       20              
  Lines        1457     1456       -1     
  Branches      298      315      +17     
==========================================
- Hits         1106     1105       -1     
  Misses        293      293              
  Partials       58       58              

Files	Coverage Δ
persim/_version.py	100.00% <100.00%> (ø)
persim/landscapes/transformer.py	83.87% <100.00%> (ø)
persim/images.py	73.19% <62.35%> (-0.09%)	⬇️

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[catanzaromj]

@ctralie @curieux This PR is ready to be reviewed. Sorry for some extraneous changes--I run black on everything by default. I can squash some of the commits too.

[curieux]

looks good to me.

[curieux]

The code coverage decreased but that's just because of line spacing I think -- not a big deal.
A followup issue should address code coverage.